Efficacy of removing Candida albicans from orthodontic acrylic bases: an in vitro study.

BACKGROUND: This study evaluated the efficacy of four methods in removing Candida albicans from the acrylic base material used to fabricate removable orthodontic appliances. METHODS: Heat-processed bars of orthodontic acrylic were incubated in a suspension of C. albicans for 2 h at 37 °C. Samples were allocated into five groups (five bars per group) according to the cleaning method: (1) manual brushing using a toothbrush; (2) soaking in a commercial denture cleaning solution; (3) soaking in a commercial mouthwash solution; (4) using an ultrasonic cleaner; and (5) soaking in distilled water as a negative control. Yeast remaining attached to the bars after cleaning were removed by vortexing in growth medium and plated on Sabouraud dextrose agar. The reduction in yeast colony count after cleaning was calculated and expressed as the number of colony forming units per acrylic bar (CFU/bar). The experiment was carried out three times. RESULTS: All four cleaning methods resulted in a significant decrease in viable yeast cells associated with the acrylic bars compared to the control group. The mean percentage reduction in viable yeast cells affected by the cleaning methods was: brushing 89.9%; chlorhexidine 95.8%; ultrasonic cleaning 99.9%; and denture tablet 100%. CONCLUSIONS: All four methods evaluated in this study were effective, to some extent, in removing C. albicans from orthodontic acrylic samples. The most effective, and readily available, cleaning method was the use of commercial denture sterilizing tablets.

An evaluation of two types of nickel-titanium wires in terms of micromorphology and nickel ions' release following oral environment exposure.

BACKGROUND: This study aimed to compare superelastic and heat-activated nickel-titanium orthodontic wires' surface morphology and potential release of nickel ions following exposure to oral environment conditions. METHODS: Twenty-four 20-mm-length distal cuts of superelastic (NiTi Force I®) and 24 20-mm-length distal cuts of heat-activated (Therma-Ti Lite®) nickel-titanium wires (American Orthodontics, Sheboygan, WI, USA) were divided into two equal groups: 12 wire segments left unused and 12 segments passively exposed to oral environment for 1 month. Scanning electron microscopy and atomic force microscopy were used to analyze surface morphology of the wires which were then immersed in artificial saliva for 1 month to determine potential nickel ions' release by means of atomic absorption spectrophotometer. RESULTS: Heat-activated nickel-titanium (NiTi) wires were rougher than superelastic wires, and both types of wires released almost the same amount of Ni ions. After clinical exposure, more surface roughness was recorded for superelastic NiTi wires and heat-activated NiTi wires. However, retrieved superelastic NiTi wires released less Ni ions in artificial saliva after clinical exposure, and the same result was recorded regarding heat-activated wires. CONCLUSIONS: Both types of NiTi wires were obviously affected by oral environment conditions; their surface roughness significantly increased while the amount of the released Ni ions significantly declined.

The C terminus of lettuce mosaic potyvirus cylindrical inclusion helicase interacts with the viral VPg and with lettuce translation eukaryotic initiation factor 4E.

Recessive resistance to lettuce mosaic virus (LMV) is conferred in lettuce by the mo1 gene, encoding the eukaryotic translation initiation factor 4E (eIF4E). The C terminus of the viral cylindrical inclusion helicase (CI-Cter), together with the VPg, is involved directly in overcoming mo1 resistance. In this study, recombinant LMV VPg and CI-Cter proteins from wild-type or resistance-breaking isolates were expressed and purified from Escherichia coli. The allelic forms of eIF4E from susceptible or resistant lettuce cultivars were produced similarly and these proteins were used in ELISA-based assays to demonstrate the in vitro binding of the various forms of LMV CI-Cter to both lettuce eIF4E and LMV VPg proteins. All combinations tested displayed significant and specific interactions, and the interaction between the C-terminal part of the LMV CI and eIF4E was confirmed in vivo in bimolecular fluorescence complementation assays. Higher interaction signals for both CI-eIF4E and CI-VPg were observed for LMV-E, indicating that the eIF4E interaction network involving CI and VPg appears to be stronger in the case of this resistance-breaking isolate. This could suggest the need for a minimal interaction threshold for infection success in resistant lettuce, but more precise measurement of the interaction parameters linking eIF4E, VPg and CI is needed in order to reinforce such a hypothesis.

Suprasellar choristoma.

A case of choristoma of the posterior lobe of the pituitary is presented. The clinical presentation suggested chromophobe pituitary adenoma and the true diagnosis was only established on histological esamination. Despite the patient's advanced age her-operative course was satisfactory, but the disturbances of endocrine and visual function remained virtually unchanged. Perusal of the literature shows that this is the twentieth case of suprasellar or neurohypophyseal choristoma so far published. It provides an opportunity to review the clinical presentation, radiology and treatment, as well as to discuss the histiogenesis and nature of this rare pituitary tumor.

[Germinoma (ectopic pinealoma) with double location : supra-sellar and the cerebellum without pineal tumour (author's transl)]. / Germinome (pinéalome ectopique) a double localisation : supra-sellaire et cérébelleuse sans tumeur pinéale.

The now nine years old girl with growth retardation, started to be ill with otitis and then diabetes insipidus of central origin at 1974. A treatment with lysin-vasopressin is prescribed. The PNEG in May 1976 shows a little, pea like, suspicious, supra-sellar nodule who is not surgically explored since they was no ophtalmologic symptoms and because a normal CT scan. Corticoid and thyroid substitutive therapy is added until September 1977 when the general status becomes impaired and vomiting starts. Also because some visual loss, a new neuroradiological study is performed showing a supra-sellar tumour and a fourth ventricle mass. The CT scan asserts the double intracranial expansive process and a posterior fossa craniotomy is done with subtotal resection of a vermian tumour and Torkildsen drainage. The histology is : Immature Dysembryoma (seminoma type) or germinoma. The follow-up was good under hormonal care. X Rays Therapy over the posterior fossa, the suprasellar region, the brain and the spinal channel was instaured. Four months later, the CT scan shows normal sized ventricles and no tumour mass at all. This case gives the authors opportunity for comments and to study the concerned literature.

[Action of hemocoagulase on the cicatrization of the dura mater in rabbits. Preliminary results]. / Action de l'hémocoagulase sur la cicatrisation de la dure-mère du lapin. Résultats préliminaires.

The present study compares the cicatrization of the dura by administration of I.M. hemocoagulase. This study was done on 6 rabbits and 6 control animals. The authors think that the cicatrization is a little slower but of better quality. The hemocoagulase seems to favorize the vasculo-exsudative process of cicatrization. The fibrinous deposits are more important too. Perhaps the occlusion of C.S. fluid fistulas could be favorized by means of the used product. Definitive conclusions are not possible for the moment but a work on a larger scale is projected.

[Sciatica and occult sacral meningocele]. / Sciatique et méningocèle sacrée occulte

The authors present the case of a 43-years-old man who had suffered from back pain for 7 to 8 years followed by sciatic. X-rays showed an abnormal sacral cavity extending from S1 to S3. Wtih the suspicion of an occult sacral meningocoele, Dimer X radiculography showed a cystic formation at S2 which only partially filled the sacral cavity. There was also an L5-S1 disc protrusion. At operation, after exploration of the roots on both sides, it was possible to remove a disc herniation at L5-S1 on the right. Laminectomy of S1 and opening of the posterior wall of the sacral canal at S2 and S3 revealed a large cyst of epidural location, touching both S1 roots superiorly and situated behind the communicating cystic cavity seen at radiculography. Histological examination of the sacral cyst showed it to be a dura mater structure, in fact anon-communicating meningocoele.